DE10312492B4 - Zoom lens and camera - Google Patents

Abstract

A zoom lens including a first group of lenses (1) having a negative focal length, a second group of lenses (2) having a positive focal length and a third group of lenses (3) having a positive focal length, in the order from an object side, and in which the second group of lenses (2) is monotone movable from an image side (15) to the object side and the first group of lenses (1) is movable to correct a positional shift of an image surface which is accomplished with a magnification change, as the magnification is changed from one end of the short end of the focal length to the end of the long focal length, the zoom lens having the second group of lenses (2) a positive lens, a negative lens, the is a positive meniscus lens whose convex surface is opposite to the object side, and a positive lens in the order of the obj ektseite contains.

Description

The present invention relates to a zoom lens according to any one of claim 1, which can be used in a digital camera, a video camera, a silver film camera and the like, and a camera according to any one of claims 6 or 20, which is a zoom lens according to the Invention.

In recent years, digital cameras have been widely disseminated and there are far-reaching needs of users for the digital camera. In particular, users always desire high image quality and miniaturization, and high functionality and miniaturization are also desired for the zoom lens used as a taking lens.

Although there are many ideas for using the zoom lenses for the digital camera in various ways, one type which is convenient for miniaturization has a structure in which a first group of lenses has a negative focal length, a second group of lenses has a positive focal length and a third group of lenses has a positive focal length provided in an order from an object side, one iris being integral with the second group of lenses toward the object side of the second group of lenses provided is moved, and the second group of lenses moves monotonically from an image side to the object side, and the first group of lenses moves so as to correct the positional shift of the image surface to be heightened with the change in magnification, when the magnification is changed from a short focal length end to the long focal length end. Such a structure is in the JP H10-39 214A , of the JP H11-287 953 A and the JP 2001-033701 A described.

The Indian JP H10-39 214A The structure described is one of the earliest applications of the type described above, the basic structure of which has been fully disclosed, but it is insufficient from the standpoint of miniaturization, and there is a possibility for improvement.

The construction by the construction of the JP H10-392 14 A is being improved and simplification is being pursued, is one of the JP H11-287 953 A or the like is described. However, because of embodiments in the JP H11-287 953 A However, it is not said that an arrangement for further miniaturization is sufficiently performed.

On the other hand, in the embodiments described in the JP 2001-033701 A Although, the surface of both sides of an air lens formed in the first group is formed to be the aspherical surface because plastic having a low refractive index is used as a lens material, no sufficient aberration correction is performed.

In the in the JP H10-39 214A As described, the recording angle of a wide-angle end is about 72 ° and it is not said that the viewing angle is sufficiently wide.

From the US 5,434,710 A For example, a zoom lens with a lens arrangement is known, whose first lens group comprises three lenses which requires an arrangement of two further lens groups which can be moved over a large adjustment range and is therefore not particularly suitable for miniaturization. Corresponding zoom lenses are also from the US 5,969,878 A and the US 6,498,688 B2 known.

It is a first object of the invention to provide a zoom lens that can be further miniaturized.

It is a second object of the invention to provide a high-performance zoom lens which can realize a resolution adaptable to an image sensor having three million picture elements to five million picture elements while the zoom lens has a compact size and the wide-angle view.

It is a third object of the invention to provide a camera which is compact and has high image quality and in which the zoom lens, which can be further downsized, is used as an optical pickup system.

According to the invention, the advantages thereof are based on a zoom lens having the features of one of the claims 1 and 9 and on a camera having the features of one of the claims 6 and 22 to 23. According to the invention, an information terminal according to claims 7 and 8 is also proposed. Advantageous embodiments will become apparent from the dependent claims.

Brief description of the illustrations

1 Fig. 12 is an illustration of an optical arrangement showing Embodiment 1 of a zoom lens according to the invention;

2 Fig. 13 is an illustration of an optical arrangement showing an embodiment 2 of the zoom lens according to the invention;

3 Fig. 12 is an illustration of an optical arrangement showing an embodiment 3 of the zoom lens according to the invention;

4 Fig. 12 is an illustration of an optical arrangement showing the embodiment 4 of the zoom lens according to the invention;

5 Fig. 12 is a view of an aberration curve at an end of a short focal length of the zoom lens according to Embodiment 1;

6 Fig. 12 is a view of the aberration curve at a medium focal length of the zoom lens according to the embodiment 1;

7 Fig. 12 is a view of an aberration curve at the end of a long focal length of the zoom lens according to Embodiment 1;

8th Fig. 12 is a view of an aberration curve at the end of the short focal length of the zoom lens according to Embodiment 2;

9 Fig. 12 is a view of the aberration curve at the center focal length of the zoom lens according to Embodiment 2;

10 Fig. 12 is a view of an aberration curve at the end of the long focal length of the zoom lens according to Embodiment 2;

11 Fig. 12 is a view of an aberration curve at the end of the short focal length of the zoom lens according to Embodiment 3;

12 Fig. 12 is a view of the aberration curve at the average focal length of the zoom lens according to Embodiment 3;

13 Fig. 12 is a view of the aberration curve at the end of the long focal length of the zoom lens according to Embodiment 3;

14 Fig. 12 is a view of an aberration curve at the end of the short focal length of the zoom lens according to Embodiment 4;

15 FIG. 12 is a view of the aberration curve at the intermediate focal length of the zoom lens according to Embodiment 4; FIG.

16 Fig. 12 is a view of the aberration curve at the end of the long focal length of the zoom lens according to Embodiment 4;

17 Fig. 12 is an illustration of an optical arrangement showing an embodiment 5 of a zoom lens according to the invention;

18 Fig. 12 is an illustration of an optical arrangement showing an embodiment 6 of the zoom lens according to the invention;

19 Fig. 12 is an illustration of an optical arrangement showing an embodiment 7 of a zoom lens according to the invention;

20 Fig. 12 is an illustration of an optical arrangement showing an embodiment 8 of a zoom lens according to the invention;

21 Fig. 12 is an illustration of an aberration curve at the end of the short focal length of the zoom lens of Embodiment 5;

22 Fig. 12 is a view of the aberration curve at the intermediate focal length of the zoom lens of Embodiment 5;

23 Fig. 10 is a view of the aberration curve at the end of the long focal length of the zoom lens of the embodiment 5;

24 Fig. 12 is a view of an aberration curve at the end of the short focal length of the zoom lens of the embodiment 6;

25 Fig. 12 is a view of the aberration curve at the intermediate focal length of the zoom lens of the embodiment 6;

26 Fig. 12 is a view of the aberration curve at the end of the long focal length of the zoom lens of the embodiment 6;

27 Fig. 12 is a view of the aberration curve at the end of the short focal length of the zoom lens of the embodiment 7;

28 Fig. 12 is a view of the aberration curve at the intermediate focal length of the zoom lens of the embodiment 7;

29 Fig. 12 is a view of the aberration curve at the end of the focal length of the zoom lens of the embodiment 7;

30 Fig. 12 is a view of an aberration curve at the end of the short focal length of the zoom lens of the embodiment 8;

31 Fig. 12 is a view of the aberration curve at the intermediate focal length of the zoom lens of the embodiment 8;

32 Fig. 12 is a view of the aberration curve at the end of the long focal length of the zoom lens of the embodiment 8;

33 shows an example of a camera according to the invention or a non-inventive portable information terminal, wherein 33 (a) is a perspective view taken from an obliquely forward direction,

33 (b) is a perspective view showing a different mode of operation, which is taken from an obliquely forward direction, and

33 (c) Fig. 12 is a perspective view taken from an obliquely rearward direction;

34 Fig. 10 is a block diagram showing an example of a signal processing system of the camera or the portable information terminal;

35 Fig. 10 is a sectional view showing a lens assembly of the zoom lens according to Embodiment 9;

36 Fig. 10 is a sectional view showing a lens assembly of the zoom lens according to Embodiment 10;

37 Fig. 10 is a sectional view showing a lens assembly of the zoom lens according to Embodiment 11;

38 Fig. 10 is a sectional view showing a lens assembly of the zoom lens according to the embodiment 12;

39 Fig. 10 is a sectional view showing a lens assembly of the zoom lens according to the embodiment 13;

40 Fig. 10 is a sectional view showing a lens assembly of the zoom lens according to the embodiment 14;

41 Fig. 10 is a sectional view showing a lens assembly of the zoom lens according to Embodiment 15;

42 Fig. 12 is a view of an aberration curve at the end of the short focal length of the zoom lens according to Embodiment 9;

43 FIG. 12 is a view of the aberration curve at the intermediate focal length of the zoom lens according to Embodiment 9; FIG.

44 Fig. 12 is a view of the aberration curve at the end of the long focal length of the zoom lens according to Embodiment 9;

45 Fig. 12 is a view of an aberration curve at the end of the short focal length of the zoom lens according to the embodiment 10;

46 FIG. 12 is a view of the aberration curve at the intermediate focal length of the zoom lens according to the embodiment 10; FIG.

47 Fig. 12 is a view of the aberration curve at the end of the long focal length of the zoom lens according to the embodiment 10;

48 Fig. 12 is a view of an aberration curve at the end of the short focal length of the zoom lens according to the embodiment 11;

49 FIG. 12 is a view of the aberration curve at the intermediate focal length of the zoom lens according to the embodiment 11; FIG.

50 Fig. 12 is a view of the aberration curve at the end of the long focal length of the zoom lens according to the embodiment 11;

51 Fig. 12 is a view of an aberration curve at the end of the short focal length of the zoom lens according to the embodiment 12;

52 FIG. 12 is a view of the aberration curve at the intermediate focal length of the zoom lens according to the embodiment 12; FIG.

53 Fig. 12 is a view of the aberration curve at the end of the long focal length of the zoom lens according to the embodiment 12;

54 Fig. 12 is a view of an aberration curve at the end of the short focal length of the zoom lens according to the embodiment 13;

55 Fig. 12 is a view of the aberration curve at the intermediate focal length of the zoom lens according to the embodiment 13;

56 Fig. 12 is a view of the aberration curve at the end of the long focal length of the zoom lens according to the embodiment 13;

57 Fig. 12 is a view of an aberration curve at the end of the short focal length of the zoom lens according to the embodiment 14;

58 Fig. 12 is a view of the aberration curve at the intermediate focal length of the zoom lens according to the embodiment 14;

59 Fig. 12 is a view of the aberration curve at the end of the long focal length of the zoom lens according to the embodiment 14;

60 Fig. 12 is a view of an aberration curve at the end of the short focal length of the zoom lens according to the embodiment 15;

61 FIG. 12 is a view of the aberration curve at the intermediate focal distance of the zoom lens according to the embodiment 15; FIG. and

62 FIG. 16 is a view of the aberration curve at the end of the long focal length of the zoom lens according to Embodiment 15. FIG.

Detailed description of the embodiments

Hereinafter, embodiments of the zoom lens and the camera using the zoom lens according to the invention and embodiments indicated by concrete numerical values will be described. Further, a portable information terminal will be described, which is not part of the invention.

(First kind)

The zoom lens according to the invention includes the first group of lenses having the negative focal length, the second group of lenses having the positive focal length, and the third group of lenses having the positive focal length in the order from the object side. In the case of changing the magnification from the short focal length end to the long focal length end, the second group of lenses is formed to be monotonously moved from the image side to the object side, and the first group of lenses is formed in order to correct the positional shift of the image surface, which is accomplished with the change of the magnification.

In the zoom lens including the above-described three groups of lenses having negative, positive and positive focal lengths, when the magnification is changed from the short focal length end to the long focal length end, the second group of lenses moves monotonously from the image side to the object side, and the first group of lenses moves so as to correct a positional shift of the image surface, which is handled by the change of the magnification. The second group of lenses carries at least part of the function of changing the magnification and the third group of lenses is mainly provided to space an exit pupil from the image surface.

In order to achieve the downsizing of the zoom lens having the above-described structure, it is necessary to enhance the performance of each lens group, particularly the second group of lenses which is the variable magnification group. However, in the case where the power of the second group of lenses is increased, it is difficult to correct the aberration of the second lens group. Accordingly, the aberration correction must be performed better in a virtual image produced by the first group of lenses. In order to downsize a diameter of the first group of lenses, the negative refractive power disposed on the object side and the positive refractive power disposed on the image side may be strengthened, however, in the case where the refractive power is excessive is strengthened, the correction of the aberration becomes difficult and the deterioration of the imaging function occurs.

Therefore, in the invention, the first group of lenses includes at least two lenses and an air lens formed between the two lenses, both surfaces of the air lens being formed to be aspherical surfaces. A large degree of freedom is given to the two surfaces in which heights of out-of-axis light fluxes are not so different in a manner that the adjacent two surfaces are formed. to form the aspheric surfaces of the first group of lenses, so that the off-axis function can be greatly improved. Also by providing Of the two aspheric surfaces in the various lenses, a relative eccentricity can be adjusted by arranging the lenses into a lens barrel, or lens barrel and the like, so that there is an advantage that the eccentricity is affected by each aspherical aspiration Lens has, can be eliminated.

Furthermore, the following conditional expressions according to the invention are fulfilled:
no> 1.50
ni> 1.60
where no indicates a refractive index to the d-line of the lens disposed on the object side of the air lens, and ni indicates a refractive index to the d-line of the lens or lens, respectively the image side of the air lens or virtual lens is arranged.

In the case where no is not larger than 1.50 and ni is not larger than 1.60, there can not be given sufficiently large aberration correcting ability of the first group of lenses and balance of each aberration, particularly astigmatism, distortion and of color differences of magnification can not be achieved. It is more desirable to satisfy the following conditional expressions:
no> 1.60 and
ni> 1.70.

In order to better correct any aberration, it is desirable in the zoom lens according to the invention that the first group of lenses has at least one negative lens whose surface is opposite to the larger curvature of the image side and the at least one positive lens whose surface is the one has larger curvature opposite to the object side in the order from the object side, and the two surfaces of the air lens formed between the negative lens and the positive lens are the aspherical surface. Each aberration can be effectively corrected in such a manner that the two surfaces in which the curvature is large and a refraction angle of the light beam tends to be increased are formed to be aspherical. In the structure described above, the angle of refraction of the light beam is relatively small in the surfaces except the aspheric surface, and the amount of aberration generated is small, so that the necessity. considering the surfaces other than the aspheric surface is reduced in the adjustment of the eccentricity, and there is the advantage that the adjustment can be made easily.

More specifically, the first group of lenses includes the negative lens whose surface having the larger curvature faces the image side, and the positive meniscus lens whose convex surface is opposite to the object side in order from the object side, and the two surfaces of the air lens that are between The two lenses may also be formed to be the aspherical surface. Also, the first lens group includes the negative meniscus lens whose convex surface is opposite to the object side, the negative meniscus lens whose convex surface opposes the object side and the positive lens whose surface having the larger curvature faces the object side in the order from the object side and the two surfaces of the air lens formed between the two lenses on the image side and the image side may be formed to be the aspherical surface. According to the above construction, it is advantageous for downsizing because of the simpler structure and according to the latter construction for broadening a viewing angle because the ability to correct the lock-up is increased.

In the case that the first lens group includes the negative meniscus lens whose convex surface opposes the object side, the negative meniscus lens whose convex surface is opposite to the object side, and the positive lens, the surface thereof having the larger curvature of the object side in the order of opposite to the object side, and the two surfaces of the air lens formed between the two lenses on the image side are formed to be aspherical surfaces, and it is desirable to satisfy the following conditional expressions: -20 <(Ro + Ri) / (Ro - Ri) <-3, wherein Ro indicates a radius of curvature of the surface from the object side of the air lens and Ri indicates the radius of curvature of the surface of the image side of the air lens. When (Ro + Ri) / (Ro-Ri) is not larger than -20, the power of the air lens or virtual lens becomes too small, and the distortion is amplified at the end of the farwheel. On the other hand, when (Ro + Ri) / (Ro-Ri) is not smaller than -3, the force of the air lens becomes too large although it is advantageous for correcting the distortion at the end of the wide angle. wherein the astigmatism and the comatic aberration are generated on a large scale and the off-axis function is degraded. It is further desirable to satisfy the following conditional expressions: -10 <(Ro + Ri) / (Ro - Ri) <-5.

In order to make the zoom lens according to the invention even simpler and have higher functionality, it is desirable that an iris, which is movable integrally with the second group of lenses, be provided on the object side of the second group of lenses and at least the surface close to the object side of the second group of lenses is formed to be the aspherical surface. The object side nearest surface of the second group of lenses is placed in the vicinity of the iris with the peripheral light beam having the sufficient height, and the change of the height of the light beam caused in the zooming is small, so that the spherical aberration the basis of the imaging function can be advantageously corrected by providing the aspherical surface in the vicinity of the iris.

As described above, in the zoom lens including the above-described three groups of lenses having the negative, positive and positive focal lengths when the magnification is changed from the short focal length end to the long focal length end, the second group of lenses is formed to be monotonically moved from the image side to the object side, and the first group of lenses is formed so as to be movable to correct the positional shift of the image surface, which is made by the change of the magnification. The second group of lenses contains almost the entire part of the magnification changing function, and the third group of lenses is mainly provided to space the exit pupil from the image surface. In order to achieve the miniaturization of the zoom lens having the above-described structure, it is necessary to strengthen the power of each group of lenses, particularly the second group of lenses, which is the variable magnification group. Therefore, the good aberration correction must be done in the second group of lenses.

In the invention, the second group of lenses in order from the object side includes the positive lens, the negative lens whose convex surface opposes the object side, the positive meniscus lens whose convex surface opposes the object side, and the positive lens though this structure Based on a so-called triplet type, in which the positive lenses are disposed between the two sides of the negative lens, the degree of freedom of the off-axis aberration correction is increased by dividing the positive lens on the image side into two parts is. Accordingly, even if the imaging angle of view is widened, the comatic aberration, the astigmatism and the like can be effectively corrected.

To obtain the higher functionality of the zoom lens, it is desirable to satisfy the following conditional expressions: 1.0 <(Rn + Rp) / 2Ymax <1.5 and -0.05 <(Rn × Rp) / (Rn + Rp) <0, where Rn indicates the radius of curvature of the surface of the image side of the negative meniscus lens in the second group, Rp indicates the radius of curvature of the surface on the object side of the positive meniscus lens, and Ymax indicates the maximum image height.

When (Rn + Rp) / 2Ymax is not larger than 1.0, the power of the two surfaces becomes too strong and it is difficult to maintain the balance of the aberration when (Rn + Rp) / 2Ymax is not less than 1 5, wherein the power of the two surfaces becomes too small and it is difficult to sufficiently obtain the aberration correcting ability, and it is difficult to perform the good aberration correction in both cases. If (Rn * Rp) / (Rn + Rp) is in the range of the conditional expressions, the spherical aberration can best be corrected. It is further desirable to satisfy the following conditional expression: 1.1 <(Rn + Rp) / 2Ymax <1.3.

In the zoom lens according to the invention, the negative meniscus lens and the positive meniscus lens may be cemented on their image side surfaces of the second group to reduce the performance deterioration caused by arrangement errors of the lenses. On the image side surface of the negative meniscus lens and the object side surface of the positive meniscus lens, the deterioration of the imaging function caused by the relative eccentricity of these two lenses is large because the aberrations of directions in which the aberrations cancel each other are generated extensively. However, the deterioration of the imaging function can be avoided by fixing the two meniscus lenses.

In the case where both meniscus lenses are cemented, it is desirable to satisfy the following conditional expression to obtain a zoom lens having a better function: 0.8 <Rc / Ymax <1.2, where Rc indicates the radius of curvature of the attachment surface, and Ymax indicates the maximum image height. If Rc / Ymax is not larger than 0.8, the power of the fixing surfaces becomes too strong and it becomes difficult to maintain the balance of aberration when Rc / Ymax is not less than 1.2, and the force refractive power of the fixing surfaces becomes too small and it becomes difficult to obtain the sufficient correctability of the aberration, and it becomes difficult to perform the good aberration correction in both cases. It is further desirable to satisfy the following conditional expression: 0.9 <Rc / Ymax <1.1.

In order for the zoom lens according to the invention to be simpler and of higher functionality, it is desirable that an iris, which is moved integrally with the second group of lenses, be provided on the object side of the second group of lenses, and at least the surface, which is closest to the object side of the second lens group is formed to be the aspherical surface. The surface closest to the object side of the second group of lenses is located near the iris, with the peripheral light beam having the sufficient height, and the change in the height of the light beam caused by the zooming is small, so that the spherical aberration that is the basis of the imaging function can be advantageously corrected by providing the aspherical surface in the vicinity of the iris. In the lens of the second group on the main object side, not only the object side surface but also the image side surface may be more desirably formed to be the aspherical surface.

Concrete embodiments of the zoom lens according to the invention are shown below by the numerical values. The aberration of the zoom lens according to the invention is sufficiently corrected and is adaptable to a photodetector having two million pixels by 4 million pixels in the case of the application to the digital camera. From the embodiment, it becomes clear that while the sufficient reduction is achieved, the excellent imaging function can be ensured in such a manner that the zoom lens according to the invention is formed.

f:

Brennweite des gesamten Systems

F:

F-Zahl

ω:

halber Sichtwinkel

R:

Krümmungsradius

D:

Abstand zwischen Oberflächen

Nd:

Brechungsindex zur d-Linie

νd:

Abbé-Zahl

K:

Konische Konstante

A4:

quadratischer asphärischer Koeffizient

A6:

asphärischer Koeffizient einer Form sechsten Grades

A8:

asphärischer Koeffizient einer Form achten Grades

A10:

asphärischer Koeffizient einer Form zehnten Grades

The meanings of the characters in the embodiment are as follows:

f:

Focal length of the entire system

F:

F-number

ω:

half view angle

R:

radius of curvature

D:

Distance between surfaces

Nd:

Refractive index to the d-line

vd:

Abbe number

K:

Conic constant

A4:

square aspheric coefficient

A6:

aspherical coefficient of a sixth degree form

A8:

aspheric coefficient of a form of eighth degree

A10:

aspheric coefficient of a tenth degree form

However, when an inverse number of a paraxial curvature radius (paraxial curvature) is set to C, and a height from an optical axis is set to H, the aspheric surface used in the embodiment is defined by the following Equation 1. Equation 1

Embodiment 1

1 shows the optical arrangement of the zoom lens according to the embodiment 1 1 are a first group of lenses 1 that have the negative focal length, a second group of lenses 2 that have the positive focal length, a third group of lenses 3 that have the positive focal length and different types of filters 12 in the order from the object side (left side in 1 ), wherein the zoom lens is the first group of lenses 1 , the second group of lenses 2 and the third group of lenses 3 contains. In the case of changing the magnification from the end of the short focal length to the end of the long focal length, the second group of lenses becomes 2 designed to be monotone and linear from the side of an image 15 to be moved to the object side, and the first group of lenses 1 and the third group of lenses 3 are moved so as to correct the shift of the position of the imaging surface, which is accomplished by changing the magnification. The first group of lenses 1 has two lenses L1 and L2 and an air lens formed between the two lenses. Both sides of the air lens, ie, the image side surface of the lens L1 and the object side surface of the lens L2 are formed to be aspherical surfaces. The lens L1 constituting the first group described above is constituted by the negative meniscus lens in which the surface having the large curvature faces the image side, and the lens L2 is formed by the positive meniscus lens in which the surface of the larger curvature the object side is opposite.

The second group of lenses 2 includes a biconvex lens L3, a biconcave lens L4 cemented to the lens L3, and a biconvex lens L5 in the order from the object side. An iris 11 that integrates with the second group of lenses 2 is arranged on the front side, ie the object side of the second group of lenses 2 at the appropriate distance.

The third group of lenses 3 contains a biconvex lens 6 , In the 1 R1, R2, ... show a curved surface in the order from the object side and D1, D2, .... show the distance between the curved surfaces in the order from the object side. The same ingredients are also used in other embodiments.

The numerical values of Embodiment 1 are shown below. The 5 FIG. 16 shows the aberration curve at the end of the short focal length of the zoom lens according to Embodiment 1, FIG 6 shows the aberration curve at the inter-focal distance, and 7 shows the aberration curve at the end of the long focal length of the zoom lens.

Embodiment 1

• f = 5.80 x 14.16, F = 2.81 x 4.42, ω = 40.07 x 18.24

Aspherical surface; second surface

• K = 0.83389, A4 = -2.39153 × 10 ^-5 , A6 = 5.82936 × 10 ^-6 , A8 = 2.27984 × 10 ^-7 , A10 = 3.12350 × 10 ⁹

Aspherical surface, third surface

• K = 0.14308, A4 = 6.13477 × 10 ^-6 , A6 = 7.36155 × 10 ^-7 , A8 = -4.44635 × 10 ^-8 , A10 = 8.38997 × 10 ^-10

Aspherical surface, sixth surface

• K = -0.36782, A4 = -7.15076 × 10 ^-5 , A6 = -1.86198 × 10 ^-6 , A8 = 1.81040 × 10 ^-7 , A10 = -6.28811 × 10 ^-9

Aspherical surface, eleventh surface

• K = -0.41879, A4 = -9.75228 x 10 ^-5 , A6 = 4.51237 x 10 ^-6 , A8 = -1.51236 x 10 ^-7 , A10 = 2.377344 x 10 ^-8

Variable distance End of short focal length Between focal distance End of the long focal length f = 5.80 f = 10.321 f = 14.159 A 14,120 4,790 1,700 B 1,563 9.120 15.520 C 4,712 4,022 3,090

The embodiment 2, which in 2 will now be described below. Embodiment 2 corresponds to the invention as described in claim 4, and differs from embodiment 1 in that the first group of lenses 1 includes the negative meniscus lens L1 whose convex surface is opposite to the object side, the negative meniscus lens L2, the convex surface of which is the object side and the positive lens L3 in which the surface of the larger curvature faces the object side. The second group of lenses 2 includes the lens L4, the lens L5 and the lens L6 and the third group of lenses 3 which includes a lens L7 is the same optical arrangement as that of the second group of lenses and the third group of lenses according to the embodiment 1.

The numerical values of Embodiment 2 are shown below. The 8th FIG. 16 shows the aberration curve at the end of the short focal length of the zoom lens according to Embodiment 2, FIG 9 shows the aberration curve at the intermediate focal length and the 10 shows the aberration curve at the end of the long focal length of the zoom lens.

Embodiment 2

• f = 5.80 x 14.50, F = 3.15 x 4.90, ω = 40.11 x 18.05

Aspherical surface; fourth surface

• K = -1.34743, A4 = -2.47950 × 10 ^-4 , A6 = -1.39275 × 10 ^-6 , A8 = -1.53180 × 10 ^-7 , A10 = 2.75855 × 10 ⁹

Aspherical surface, fifth surface

• K = -0.61459, A4 = -1.46495 x 10 ^-4 , A6 = 1.18096 x 10 ^-6 , A8 = -1.63712 x 10 ^-7 , A10 = 3.7570 x 10 ^-9

Aspherical surface, eighth surface

• K = -0.31246, A4 = -6.66353 × 10 ^-5 , A6 = -2.44299 × 10 ^-6 , A8 = 2.63958 × 10 ^-7 , A10 = -1.04190 × 10 ^-8

Aspherical surface, thirteenth surface

• K = 0.41267, A4 = -3.69517 × 10 ^-5 , A6 = 4.47121 × 10 ^-6 , A8 = -2.16080 × 10 ^-7 , A10 = 3.96634 × 10 ^-9

Variable distance End of short focal length Between focal distance End of the long focal length f = 5.80 f = 9.16 f = 14.50 A 15,164 6,403 1,500 B 2,790 7,837 17.561 C 4,905 4,859 3,062

Numeric values of the conditional expression

• (R _o + R _i ) / (R _o - R _i ) = -7,490

The embodiment 3, which in 3 is shown below. Embodiment 3 has the structure in which a convex lens is added to the second group of lenses 2 according to Embodiment 2, that is, the structure in which a convex lens is divided into two pieces. In fact, the first group contains lenses 1 the negative meniscus lens L1, the negative lens L2 and the positive lens L3, the second group of lenses 2 the positive lens L4, the negative lens L5, the positive lens L6 and the positive lens L7, and the third group of lenses 3 contains a negative meniscus lens L8. An iris 11 moves integrally with the second group of lenses 2 ,

The numerical values of Embodiment 3 are shown below. The 11 FIG. 12 shows the aberration curve at the end of the short focal length of the zoom lens according to Embodiment 3, FIG 12 shows the aberration curve at the intermediate focal point or the intermediate focal point, and 13 shows the aberration curve at the end of the long focal length of the zoom lens.

Embodiment 3

• f = -5.97 x 14.48, F = 2.59 x 3.94, ω = 39.28 x 17.60

Aspherical surface; fourth surface

• K = -1.33292, A4 = -2.34334 × 10 ^-4 , A6 = -3.74018 × 10 ^-7 , A8 = -2.05904 × 10 ^-7 , A10 = 3.63798 × 10 ⁹

Aspherical surface, fifth surface

• K = -0.50499, A4 = -1.34722 × 10 ^-4 , A6 = -1.18096 × 10 ^-7 , A8 = -1.35982 × 10 ^-7 , A10 = 2.86855 × 10 ^-9

Aspherical surface, eighth surface

• K = -0.46683, A4 = -2.94708 x 10 ^-5 , A6 = -1.09262 x 10 ^-6 , A8 = 9.90847 x 10 ^-8 , A10 = -1.99265 x 10 ^-9

Aspherical surface, fifteenth surface

• K = -427.29332, A4 = -1.90428 × 10 ^-4 , A6 = 3.37589 × 10 ^-6 , A8 = 2.14846 × 10 ^-7 , A10 = -3.87038 × 10 ^-9

Variable distance End of short focal length Between focal distance End of the long focal length f = 5.97 or focal distance f = 14.48 f = 9.17 A 14,224 6,767 1,820 B 2,096 7,045 15.535 C 4,894 4,438 3,067

Numerical values of the conditional expression or the conditional equation

• (R _o + R _i ) / (R _o - R _i ) = -7,923

The embodiment 4, which in 4 will now be described below. Embodiment 4 has the structure in which the constructions of the second group of lenses 2 and the third group of lenses 3 are deformed in the embodiment 3.

The numerical values of Embodiment 4 are shown below. The 14 FIG. 16 shows the aberration curve at the end of the short focal length of the zoom lens according to Embodiment 4, FIG 15 shows the aberration curve at the Zwischenbrennweite or at the intermediate focal distance, and 16 shows the aberration curve at the end of the long focal length of the zoom lens.

Embodiment 4

• f = 5.97 x 11.26, F = 2.82 x 3.42, ω = 39.17 x 22.65

Aspherical surface; fourth surface

• K = -1.01005, A4 = -1.84076 x 10 ^-4 , A6 = -4.81141 x 10 ^-6 , A8 = -6.73366 x 10 ^-8 , A10 = -1.12720 x 10 ^-9

Aspherical surface fifth surface

• K = -0.11037, A4 = -9.77583 × 10 ^-5 , A6 = 1.77226 × 10 ^-6 , A8 = -1.90717 × 10 ^-7 , A10 = 2.13759 × 10 ^-9

Aspherical surface, eighth surface

• K = -0.40614, A4 = -1.56422 x 10 ^-5 , A6 = 2.63977 x 10 ^-6 , A8 = -4.12297 x 10 ^-7 , A10 = 2.21536 x 10 ^-8

Aspherical surface, fifteenth surface

• K = 13.50328, A4 = -4.65994 x 10 ^-4 , A6 = 2.62615 x 10 ^-6 , A8 = -2,47424 x 10 ^-7 , A10 = 1.41575 x 10 ^-8

Variable distance End of short focal length Between focal distance End of the long focal length f = 5.97 or focal distance f = 11.26 f = 8.20 A 15,317 7,461 1,500 B 2,440 3,100 3,486 C 3,573 4,888 7,053

Numerical values of the conditional expression or the conditional equation

• (R _o + R _i ) / (R _o - R _i ) = -6.296

Embodiment 5 will be described next. As in 17 to 20 5, the embodiment 5 to embodiment 8 are characterized in that the first group of lenses 1 in the order from the object side, the negative meniscus lens L1 whose convex surface opposes the object side, the negative meniscus lens L2 whose convex surface opposes the object side, and the positive lens L3 in which the convex surface having the larger curvature of the object side opposite, and the second group of lenses 2 includes, in the order from the object side, the positive lens L4, the negative meniscus lens L5 whose convex surface is opposite to the object side, and the positive meniscus lens L6 whose convex surface is opposite to the object side, and the positive lens L7. Each of the third group of lenses 3 contains a positive lens L8. Each of Embodiment 5 to Embodiment 8 is with the iris 11 provided integral with the second group of lenses 2 is moved on the object side. In each of Embodiment 5 to Embodiment 8, the surface of the second group of lenses is 2 , which is placed on the most object side or main object side, is formed to be the aspherical surface.

The 17 shows the optical arrangement of the zoom lens according to embodiment 5. The numerical values of embodiment 5 are shown below. The 21 FIG. 12 shows the aberration curve at the end of the long focal length of the zoom lens according to Embodiment 5, FIG 22 shows the aberration curve at the intermediate focal length and the intermediate focal distance, and 23 shows the aberration curve at the end of the long focal length of the zoom lens.

Embodiment 5

• f = 5.97 × 16.88, F = 2.65 × 4.42, ω = 39.23 × 15.53

Aspherical surface; fourth surface

• K = 0.00, A4 = -0.390444 × 10 ^-3 , A6 = -0.814745 × 10 ^-6 , A8 = 0.405425 × 10 ^-6 , A10 = -0.237422 × 10 ^-7 , A12 = 0.383887 × 10 ^-9 , A14 = -0.300058 × 10 ^-12 , A16 = -0.147703 × 10 ^-12 , A18 = 0.135176 × 10 ^-14

Aspherical surface, eighth surface

• K = 0.0, A4 = -0.119781 × 10 ^-3 , A6 = -0.957080 × 10 ^-6 , A8 = -0.12005 × 10 ^-7 , A10 = -0.474520 × 10 ^-9

Aspherical surface, fifteenth surface

• K = 0.0, A4 = 0.626695 × 10 ^-4 , A6 = -0.153604 × 10 ^-6 , A8 = 0.274416 × 10 ^-6 , A10 = -0.231852 × 10 ^-7

Aspherical surface, sixteenth surface

• K = 0.0, A4 = -0.448058 × 10 ^-4 , A6 = 0.463819 × 10 ^-5 , A8 = -0.228407 × 10 ^-6 , A10 = 0.437430 × 10 ^-5

Variable distance End of short focal length Intermediate focal length or End of the long focal length f = 5.97 Between focal length f = 16.875 f = 10.044 A 20,635 8.566 1,584 B 2,137 8.266 18.481 C 5,240 4,611 3,042

Numerical values of the conditional expression or the conditional equation

• _(N R + R _p) / 2Y _max = 1.193
• (R _n - R _p) / (R _s + R _p) = -0.038

The 18 shows the optical arrangement of the zoom lens according to embodiment 6. The numerical values of the embodiment 6 are shown below. The 24 FIG. 12 shows the aberration curve at the end of the short focal length of the zoom lens according to Embodiment 6, FIG 25 shows the aberration curve at the average focal distance and the average focal distance, and 26 shows the aberration curve at the end of the long focal length of the zoom lens.

Embodiment 6

• f = 5.97 x 16.88, F = 2.61 x 4.42, ω = 39.23 x 15.54

Aspherical surface; fourth surface

• K = 0.00, A4 = 0.411852 × 10 ^-3 , A6 = 0.753431 × 10 ^-6 , A8 = 0.358811 × 10 ^-6 , A10 = -0.236179 × 10 ^-7 , A12 = 0 , 497070 × 10 ^-9 , A14 = -0.339446 × 10 ^-12 , A16 = -0.155371 × 10 ^-12 , A18 = 0.133056 × 10 ^-14

Aspherical surface, eighth surface

• K = 0.0, A4 = -0.110542 × 10 ^-3 , A6 = -0.134632 × 10 ^-5 , A8 = 0.633679 × 10 ^-7 , A10 = -0.284499 × 10 ^-8

Aspherical surface, fourteenth surface

• K = 0.0, A4 = 0.547595 × 10 ^-4 , A6 = 0.153645 × 10 ^-5 , A8 = -0.425020 × 10 ^-7 , A10 = -0.403161 × 10 ^-9

Aspherical surface, fifteenth surface

• K = 0.0, A4 = -0.318733 × 10 ^-4 , A6 = 0.350103 × 10 ^-5 , A8 = -0.156928 × 10 ^-6 , A10 = 0.311523 × 10 ^-8

Variable distance End of short focal length Intermediate focal length or End of the long focal length f = 5.97 Between focal length f = 16.88 f = 10.05 A 19,937 8.125 1,653 B 2,091 8,138 19.386 C 5,563 5,198 1,061

Numerical values of the conditional expression or the conditional equation

• R _c / Y _max = 1.094

The 19 shows the optical arrangement of the zoom lens according to Embodiment 7.

The numerical values of Embodiment 7 are shown below. The 27 FIG. 16 shows the aberration curve at the end of the short focal length of the zoom lens according to Embodiment 7, FIG 28 shows the aberration curve at the intermediate focal length and the intermediate focal distance, and 29 shows the aberration curve at the end of the long focal length of the zoom lens.

Embodiment 7

• f = 5.97 x 16.87, F = 2.62 x 4.51, ω = 39.24 x 15.54

Aspherical surface; fourth surface

• K = 0.00, A4 = -0.375046 × 10 ^-3 , A6 = -0.737622 × 10 ^-6 , A8 = 0.422576 × 10 ^-6 , A10 = -0.260845 × 10 ^-7 , Al2 = 0.593641 × 10 ^-9 , A14 = -0.122582 × 10 ^-11 , A16 = -0.185556 × 10 ^-12 , A18 = 0.214071 × 10 ^-14

Aspherical surface, eighth surface

• K = 0.0, A4 = -0.910992 × 10 ^-4 , A6 = -0.261147 × 10 ^-6 , A8 = -0.373517 × 10 ^-7 , A10 = 0.783826 × 10 ^-8

Aspherical surface, fourteenth surface

• K = 0.0, A4 = 0.203369 × 10 ^-3 , A6 = -0.582416 × 10 ^-6 , A8 = 0.540790 × 10 ^-6 , A10 = -0.224755 × 10 ^-7

Aspherical surface, fifteenth surface

• K = 0.0, A4 = 0.206221 x 10 ^-4 , A6 = -0.465805 x 10 ^-5 , A8 = 0.996942 x 10 ^-7 , A10 = 0.177863 x 10 ^-8

Aspherical surface, sixteenth surface

• K = 0.0, A4 = 0.449165 × 10 ^-4 , A6 = -0.899826 × 10 ^-5 , A8 = 0.228409 × 10 ^-6 , A10 = 0.737490 × 10 ^-9

Variable distance End of short focal length Between focal distance End of the long focal length f = 5.97 or focal distance f = 16.87 f = 10.04 A 18,875 7.310 1,600 B 1,887 7,140 18.785 C 5,175 5.375 2,840

Numerical values of the conditional expression or the conditional equation

• R _c / Y _max = 1.075

The 20 shows the optical arrangement of the zoom lens according to the embodiment 8. The numerical values of the embodiment 8 are shown below. The 30 FIG. 12 shows the aberration curve at the end of the short focal length of the zoom lens according to Embodiment 8, FIG 31 shows the Aberrationskurve at the Zwischenbrennppotstsabstand or at the Zwischenbrennweitenabstand or, and the 32 shows the aberration curve at the end of the long focal length of the zoom lens.

Embodiment 8

• f = 5.97 x 16.87, F = 2.62 x 4.51, ω = 39.24 x 15.54

Aspherical surface; fourth surface

• K = 0.00, A4 = -0.181611 × 10 ^-3 , A6 = -0.742101 × 10 ^-6 , A8 = 0.494068 × 10 ^-6 , A10 = -0.225674 × 10 ^-7 , A12 = 0.450171 × 10 ^-9 , A14 = 0.119635 × 10 ^-12 , A16 = -0.144145 × 10 ^-12 , A18 = 0.155608 × 10 ^-14

Aspherical surface, eighth surface

• K = 0.0, A4 = 0.297157 × 10 ^-4 , A6 = -0.792125 × 10 ^-5 , A8 = 0.413744 × 10 ^-6 , A10 = -0.166034 × 10 ^-7

Aspherical surface, ninth surface

• K = 0.0, A4 = 0.1331506 × 10 ^-3 , A6 = -0.922350 × 10 ^-5 , A8 = 0.410814 × 10 ^-6 , A10 = -0.166077 × 10 ^-7

Aspherical surface, fourteenth surface

• K = 0.0, A4 = 0.451929 × 10 ^-3 , A6 = 0.594516 × 10 ^-5 , A8 = 0.100562 × 10 ^-5 , A10 = 0.373888 × 10 ^-7

Aspherical surface, fifteenth surface

• K = 0.0, A4 = -0.498667 × 10 ^-4 , A6 = 0.292441610 ^-5 , A8 = -0.114195 × 10 ^-6 , A10 = 0.185420 × 10 ^-8

Variable distance End of short focal length Between focal length End of the long focal length f = 5.97 or intermediate focal length f = 16.89 f = 10.05 A 19,051 8.305 1,500 B 1,901 8,177 16.866 C 4,564 3,579 3,802

Numerical values of the conditional expression or the conditional equation

• R _c / Y _max = 0.914

The case where the above-described zoom lens according to each embodiment is used for the camera and the portable information terminal will be described.

The 33 shows an example in which the zoom lens for the digital camera described above is used. In 33 the camera has a taking lens 20 and the photodetector includes an area sensor, such as a CCD, and the camera is configured to capture the image of a photographic object that is being captured by the taking lens 20 is formed with a light receiving portion of the photodetector. The zoom lenses described in Embodiments 1 to 8 are called the taking lens and the taking lens, respectively 20 used. The digital camera that is in 33 shown has an optical viewfinder 21 , a lock button 22 or trigger 22 , a zooming lever 23 and a radiating section 24 a flash device containing a stroboscopic emitting device. The camera also has a monitor or a monitoring device 25 , which includes a liquid crystal display panel and the like, various types of operation buttons 26 , an on / off switch 29 and the like. On the back of the camera. Furthermore, the camera has a memory card slot 27 and a communication slot 28 in a side surface section.

As in 33 (a) shown is the taking lens 20 in a state of being pulled back into the body while the camera is worn on the street. As in 33 (b) a lens barrel is extended when a user turns off the on / off switch 29 pressed to turn on the power supply. At this point, each group of lenses of the zoom lens is placed, for example, at the short focal length end within the lens barrel, the array of each group of lenses being actuated by operation of the zoom control lever 23 is changed, and the change of the magnification to the end of the long focal length can be performed. The magnification of the viewfinder 21 also syncs with the change in the viewing angle of the shooting lens 20 changed.

When the shutter button or shutter release button 22 is pressed halfway, an autofocusing circuit containing a range search circuit is activated to perform the focusing. In the zoom lenses according to Embodiment 1 through Embodiment 8, the focusing can be performed by using the first group of lenses 1 or the third group of lenses 3 is moved in the direction of the optical axis direction or the photodetector in the direction of the optical axis or optical Axial direction is moved. When the lock button 22 is pressed down or down, the photograph is made. The processings after will be described later.

One format or type of application may be the camera, which is a conventional film camera, the 33 however, the example of the digital camera shows. The digital camera can also be used as the portable information terminal in which a communication function is added. In the in 33 example shown may be a memory card in the slot 27 can be inserted and a communication card can be in the slot 28 so that the digital camera can be used as the portable information terminal. The 34 Fig. 10 shows an example of a signal processing system to be able to be used as the portable information terminal.

In 34 The image of the photographic object on the light receiving portion or light receiving portion of a photodetector 32 formed containing the CCD area sensor. through the taking lens 20 , and the photodetector 32 outputs an image signal according to the formed image. The signal processing and the image processing for the image signal are performed by a signal processor 33 , an image processing device 34 and the like, which are controlled by a central processing device including a CPU, a microprocessor, or the like, and the image signal is stored in a semiconductor memory 37 recorded or saved. The semiconductor memory 37 may be built into the camera, or the semiconductor memory may be in the memory card, which is in the slot 27 is introduced. That on the semiconductor memory 37 recorded or stored image signal is in the liquid crystal monitor 25 under the control of the central processing facility 31 entered, and the image can with the liquid crystal monitor 25 be reproduced. Furthermore, the communication with the outside world via a communication card 38 be performed. in the slot 28 is introduced, and the image signal can also be transmitted to the outside world. The operation buttons 26 are used when in the semiconductor memory 37 stored image on the liquid crystal display or the liquid crystal display 25 is reproduced or transmitted to the outside world using the communication card 38 or the like is performed. The picture taken can also be on the liquid crystal monitor 25 be reproduced. Each of the slots 27 and 28 in which the semiconductor memory 37 and the communication card 38 may be used for a general purpose and in particular for a different general purpose.

The compact camera or the portable information terminal having the high-quality image using the photodetector in the range of two million pixels to four million pixels can be realized in such a manner that any one of the zoom lenses according to the embodiments of Figs 8 is used as the taking lens of a camera or the portable information terminal.

(Second kind)

Like in the 35 with reference to a zoom lens according to the invention, "in the zoom lens in which a first group I having a negative focal distance, a second group II having the positive focal length and a third group III that has the positive focal length, in order from the object side 50 (left side after 35 ), wherein an iris S which is moved integrally with the second group is provided on the object side of the second group II, and the second group II monotonously moves from the image side 52 to the object side, and the first group I moves so as to correct the positional shift of the image surface, which is achieved with the change in magnification and reduction, respectively, when the enlargement and reduction from the short focal length end to the end of the long focal length is changed, wherein the zoom lens is characterized in that the second group II is a lens 51 with three cemented elements, the negative lens, the positive lens, and the positive lens are omitted in order from the object side. "

In the zoom lens, the negative lens on the most or main object side of the three-element fixed or cemented lens can be used 51 in the second group II, have a "meniscus shape whose concave surface is the image side and the image side, respectively 52 opposite is ".

The negative lens on the main image side of the three-element cemented lens assembly 51 is disposed in the second group II, "the strongly concave surface may be opposite to the image side".

• (1) 1,45 < Nc2 < 1,52 und
• (2) 68 < νc2 < 85.

It is preferable that a refractive index Nc2 and a positive lens Abbe number νc2 disposed at the center of the three-element cemented lens array in the second group II satisfy the following conditions (claims 18 and 19):

• (1) 1.45 <Nc 2 <1.52 and
• (2) 68 <νc2 <85.

• (3) 1,60 < Nc1 < 1,95,
• (4) 20 < νc1 < 40,
• (5) 1,60 < Mc3 < 1,95, und
• (6) 20 < νc3 < 40.

In this case, it is preferable that a refractive index Nc1 and an Abbe number νc1 of the negative lens arranged on the main object side of the three-element fixed-cemented lens array in the second group II and a refractive index Nc3 and a refractive index. Number νc3 of the negative lens disposed on the most or main image side of the three-element fixed-cemented lens array in the second group II satisfying the following conditions:

• (3) 1.60 <Nc1 <1.95,
• (4) 20 <νc1 <40,
• (5) 1.60 <Mc3 <1.95, and
• (6) 20 <νc3 <40.

• (3.1) 1,75 < Nc1 < 1,95 und
• (4.1) 20 < νc1 < 35, oder die folgenden Bedingungen erfüllen:
• (3.1) 1,75 < Nc1 < 1,95 und
• (4.2) 35 ≤ νc1 < 40, oder die folgenden Bedingen erfüllen:
• (3.2) 1,60 < Nc1 ≤ 1,75 und
• (4.1) 20 < νc1 < 35.

In this case, the refractive index Nc1 and the negative lens Abbe number νc1 arranged on the main object side of the three-element cemented lens array in the second group II satisfy the following conditions:

• (3.1) 1.75 <Nc1 <1.95 and
• (4.1) 20 <νc1 <35, or satisfy the following conditions:
• (3.1) 1.75 <Nc1 <1.95 and
• (4.2) 35 ≤ νc1 <40, or satisfy the following conditions:
• (3.2) 1.60 <Nc1 ≤ 1.75 and
• (4.1) 20 <νc1 <35.

• (7) 0,5 < (Rc2/Rc4) < 0,85.

In the described zoom lens, it is preferable that a radius of curvature of the cemented surface on the object side Rc2 and a radius of curvature on the surface of the main image side Rc4 of the three-element cemented lens array in the second group satisfy the following condition:

• (7) 0.5 <(Rc2 / Rc4) <0.85.

In the described zoom object, the second group may have "at least one positive lens on either the object side or the image side of the three-element cemented lens array. In this case, it is preferable that at least one of the positive lenses located on the object side and the image side of the three-element fixed or cemented lens arrangement are arranged, the aspherical surface has.

In the described zoom lens, the first group may have (two negative lenses and one positive lens in order from the object side.

A camera apparatus according to the invention is characterized by having the zoom lens described as "an optical pickup system of a camera operation section". The camera device may be realized as "a portable information terminal apparatus". Needless to say, the camera apparatus can be realized as a digital camera apparatus or a silver film camera apparatus having the zoom lens described as the optical pickup system.

Like the zoom lens of the invention, in the zoom lens including the three lens groups whose power distribution is negative, positive and positive, generally the second group of lenses is monotonically moved from the image side to the object side and the first group of lenses is moved so as to correct the positional shift of the image surface, which is accomplished by the change of magnification or reduction, as the magnification is changed from the end of the short focal length to the end of the long focal length.

Accordingly, the second group of lenses assumes at least part of the magnification change function, and the third group of lenses is provided, primarily to space an exit pupil from the image surface.

In order to realize the zoom lens in which various kinds of aberrations are small and the resolution is high, the change of the aberration caused by the change of the magnification must be suppressed to the small amount, particularly in the second group of Lens, which is the group mainly taking on the change of magnification, so that the aberration is preferably corrected in its entire range of change of magnification.

In order to realize the wide-angle view of the end of the short focal length, it is necessary to reduce the chromatic difference of the magnification, which is increased with the broadening or widening of the viewing angle. The construction of the second group of lenses becomes important in order to advantageously correct the chromatic difference of the magnification in the entire area of the change in magnification.

The second group of lenses in the zoom lens having the structure including the three groups, one of which contains three elements of the positive, negative and positive lenses, one containing three elements of the positive, positive and negative lenses, and one containing four elements of the positive, positive, negative and positive lenses, and one containing four elements of the positive, negative, negative and positive lenses are known in the art as the second group of lenses, but the second Group of lenses in the zoom lens according to the invention allows the better aberration correctability than those of the prior art.

That is, in the zoom lens of the invention, the second group of lenses is formed to have the three-element cemented lens assembly containing the negative, positive, and negative lenses in order from the object side. Because the two surfaces of the cemented surface in the three-element fixed or cemented lens assembly differ in the distance from the iris, the two surfaces also differ in a manner in which the light beam is on-axis and off-axis passes. Accordingly, the axial chromatic aberration and the chromatic difference of the magnification can be corrected independently to a certain extent by the two surfaces of the cemented surfaces, and in particular, it is effective for correcting the chromatic difference of enlargement and reduction with the Broadening or extension of the viewing angle is increased.

With reference to a means, it is thought that two sets of fixed or cemented lenses are used, but when the optical axis between the fixed lenses is shifted by the eccentricity of the arrangement or the like, the chromatic difference of the magnification or downsizing off-axis or optical axis asymmetrically, and unnatural chromatic aberrations easily appear.

On the other hand, when the three-element fixed lens array of the invention is used, the eccentricity in the array is never generated in the two surfaces of the cemented surfaces, and the chromatic difference of the magnification can be satisfactorily reduced.

Like the zoom lens described above, when the negative lens disposed on the most object side of the three elements of the cemented lens array in the second group of lenses is formed in the meniscus shape, the concave one thereof Surface of the image side, the surface on the object side of the negative lens is formed to be the convex surface, the incident light beam is not greatly refracted, the unnecessary aberration is prevented from occurring, the spherical aberration and the chromatic aberration Can be mainly corrected by forming the surface on the image side to be the highly concave surface, and the aberration can be more advantageously corrected.

Like the zoom lens described, the negative lens disposed on the image side of the two-element cemented lens array in the second group of lenses is formed to be one in which the highly concave surface is opposite to the image side, so that strongly concave surface of the surface on the image side can perform a second correction of the spherical aberration and the chromatic aberration error aberration and can also contribute to the correction of the astigmatism, and thus the aberration can be corrected even more advantageous.

The conditions (1) and (2) are the conditions for the advantageous correction of the chromatic aberration when the refractive index Nc2 is more than 1.52 and the Abbe number νc2 is smaller than 68, wherein it is difficult to balance the axial chromatic aberration and other aberrations, in particular, the axial chromatic aberration easily occurs at the end of the long focal length. Another corrective effect of the monochromatic aberration is not obtained satisfactorily in the fixed surface on the object side.

On the other hand, if the refractive index Nc2 is smaller than 1.45 and the Abbe number νc2 is larger than 85, although it is advantageous for the correction of the aberration, glass material becomes expensive and incurs an increase in cost.

Fulfillment of conditions (1) and (2) can more advantageously correct the primary axial chromatic aberration, realize higher functionality, and result in preserving the image quality providing higher contrast.

• (3-1) 1,75 < Nc1 < 1,95 und
• (4-1) 20 < νc1 < 35, oder die Kombination von
• (3-1) 1,75 < Nc1 < 1,95 und
• (4-2) 35 ≤ νc1 < 40 oder die Kombination von
• (3-2) 1,60 < Nc1 ≤ 1,75 und
• (4-1) 20 < νc1 < 35

können die oben beschriebenen Bedingungen (3) und (4) erfüllen.The conditions (3) to (6) are the conditions for more favorably correcting the chromatic difference of enlargement and reduction, respectively. The good balance between the axial chromatic aberration and the chromatic difference of enlargement can be achieved, in particular, the chromatic difference of the magnification at the end of the short focal length can be reduced, and the correct state of the chromatic aberration can be simultaneously maintained in a manner which satisfies conditions (3) to (6), combining conditions (1) and (2). Accordingly, the higher functionality of the zoom lens can be achieved by even more advantageously correcting mainly the chromatic difference of the magnification. The combination of

• (3-1) 1.75 <Nc1 <1.95 and
• (4-1) 20 <νc1 <35, or the combination of
• (3-1) 1.75 <Nc1 <1.95 and
• (4-2) 35 ≤ νc1 <40 or the combination of
• (3-2) 1.60 <Nc1 ≤ 1.75 and
• (4-1) 20 <νc1 <35

can satisfy the conditions (3) and (4) described above.

The condition (7) described is one for the further improvement of the monochromatic aberration when a parameter Rc2 / Rc4 is larger than 0.85, the spherical aberration is slightly strong in a positive direction at the end of the long focal length , which causes the deterioration of the image contrast. On the other hand, when the parameter Rc2 / Rc4 is smaller than 0.5, the correction ability of the astigmatism and the deterioration of the image surface tend to be poor, resulting in the flatness of the image surface over the entire area of the image surface Change in magnification is deteriorated.

The satisfaction of the condition (7) can advantageously improve mainly the monochromatic aberration of the zoom lens advantageously.

The two surfaces of the concave surface having the strong and the negative refractive power in the three-element fixed or cemented lens assembly. By arranging the positive refractive force toward the negative refractive force, the corrective ability of the abberation caused by the above-described two surfaces having a concave surface can be sufficiently brought about.

As with the described zoom lens, when the second group of lenses is formed so as to have each of at least one positive lens on the object side and the image side of the three-element fixed lens array, the positive, negative, positive, negative, and positive construction as a whole is obtained from the second group of lenses, and it is well balanced for the arrangement of the refractive power. By adapting the structure, the excessive aberration can be prevented from being generated in a surface of the lens and the deterioration of the imaging function caused by manufacturing defects such as eccentricity can also be suppressed.

Accordingly, by adapting the structure, the sufficient reduction and the wide-angle view can be achieved, and the high functionality can be realized.

In order to reduce the size of the second group of lenses (in particular total length compaction), it is effective to use the aspheric surface for the second group of lenses. At this point, the aspheric surface may be provided on either side or both sides of the positive lenses disposed on the object side and the image side in the three-element cemented lens array. The positive lens on the object side is close to the iris and mainly effective in correcting spherical aberration and chromatic aberration aberation. The positive lens on the image side is far from the iris and effective in correcting the aspheric aberration in addition to the spherical aberration and the chromatic aberration aberration, because the non-axial light flux through the positive lens on the image side which passes to a certain extent separate luminous flux.

Accordingly, by adjusting the structure, the chromatic aberration can be more favorably corrected, and the zoom lens having extremely high functionality can be realized.

The first group of lenses of the zoom lens according to the invention can be arranged with three elements in the order from the object side with the negative meniscus lens whose convex surfaces are opposite to the object side, the negative lens in which the surface of the large curvature faces the image side, and the positive lens in which the surface of the large curvature is opposite to the object side, are formed. Because the structure has the high aberration correction capability deviating from the axis, it is advantageous for widening the viewing angle. In order to more positively correct the aberration, it is desirable that the surface on the image side of the above-described negative lens (the surface having the larger curvature on the image side) is the aspherical surface.

In the zoom lens according to the invention, the third group of lenses can be formed with a positive lens. Not only is the simple construction of the third group of lenses advantageous for the reduction of the lens system, but also for the simplification of the mechanism when the focusing is performed by the third lens group.

Concrete embodiments of the zoom lenses according to the invention are listed below.

As shown in the figures of the aberrations, the aberration is sufficiently corrected in each embodiment, and is sufficiently adaptable to a photodetector having three million picture elements to five million picture elements. That is, it is clear that the extremely advantageous function can be ensured in such a manner when the zoom lens is formed as in the invention while achieving sufficient miniaturization and broadening of the viewing angle.

f:

Brennweite des gesamten Systems

F:

F-Zahl bzw. -Nummer

ω:

Halber Sichtwinkel

R:

Krümmungsradius

D:

Abstand zwischen Oberflächen (einschl. Oberfläche der Iris)

Nd:

Brechungsindex

νd:

Abbé-Zahl

K:

konische Konstante

A4:

quadratisch asphärischer Koeffizient

A6:

asphärischer Koeffizient der Form 6. Grades

A8:

asphärischer Koeffizient der Form 8. Grades

A10:

asphärischer Koeffizient der Form 10. Grades

A12:

asphärischer Koeffizient der Form 12. Grades

A14:

asphärischer Koeffizient der Form 14. Grades

A16:

asphärischer Koeffizient der Form 16. Grades

A18:

asphärischer Koeffizient der Form 18. Grades

The meanings of each character in the embodiments are as follows:

f:

Focal length of the entire system

F:

F number or number

ω:

Half view angle

R:

radius of curvature

D:

Distance between surfaces (including the surface of the iris)

Nd:

refractive index

vd:

Abbe number

K:

conical constant

A4:

square aspheric coefficient

A6:

aspheric coefficient of the sixth form

A8:

aspherical coefficient of the form 8th degree

A10:

aspherical coefficient of the form 10th degree

A12:

aspherical coefficient of the form 12th degree

A14:

aspherical coefficient of the form 14th degree

A16:

aspherical coefficient of the form 16th degree

A18:

Aspheric coefficient of the 18th degree form

When the inverse number of the paraxial or near-axis curvature radius (paraxial curvature) is set to C and the height from the optical axis is set to H, the aspheric surface becomes as follows and the shape is specified by giving values of the conic constant K and the higher aspheric coefficients A4 to A18. X = CH ² [1 + √ (1 - (1 + K) C ² H ² )] + A ₂ H ⁴ + A ⁶ .H ⁸ + A ₈ .H ⁸ + A ₁₀ .H ¹⁰ + A ₁₂ .H ¹² + A ₁₄ · H ¹⁴ + A ₁₆ · H ¹⁶ + A ₁₈ · H ¹⁸

Embodiment 9:

• f = 5.97 x 16.87, F = 2.62 x 4.35, ω = 39.20 x 15.56

Aspherical surface; fourth surface

• K = 0.00, A4 = -2.88027 × 10 ^-4 , A6 = -6.01009 × 10 ^-6 , A8 = 2.79485 × 10 ^-7 , A10 = -1.38570 × 10 ^-8 , A12 = 2,75096 × 10 ^-10 , A14 = -1,20000 × 10 ^-12 , A16 = 4,50197 × 10 ^-14 , A18 = 4,89891 × 10 ^-16

Aspherical surface, eighth surface

• K = 0.0, A4 = -5.29387 x 10 ^-5 , A6 = 8.11971 x 10 ^-7 , A8 = -8.73056 x 10 ^-8 , A10 = 2.65984 x 10 ^-9

Aspherical surface, fifteenth surface

• K = 0.0, A4 = 2.60656 × 10 ^-4 , A6 = 4.73782 × 10 ^-6 , A8 = 3.71246 × 10 ^-7 , A10 = -6.41360 × 10 ^-10

Aspherical surface, sixteenth surface

• K = 0.0, A4 = -1.09895 × 10 ^-5 , A6 = 2.57475 × 10 ^-6 , A8 = -9.80625 × 10 ^-8 , A10 = 1.86997 × 10 ^-9

Variable distance End of short focal length Between focal length End of the long focal length f = 5.97 or intermediate focal length f = 10.18 f = 10.04 A 21,260 8,610 1,500 B 3,680 8,640 17.630 C 4,427 4,268 3,098

Numerical values of the conditional expression or the conditional equation

• (R _c2 / R _c4 ) = 0.687

Embodiment 10

• f = 5.97 x 16.87, F = 2.62 x 4.56, ω = 39.18 x 15.54
  

Aspherical surface; fourth surface

• K = 0.00, A4 = -2.29550 × 10 ^-4 , A6 = -3.47013 × 10 ^-6 , A8 = 2.75845 × 10 ^-7 , A10 = -1.89585 × 10 ^-8 , A12 = 5.22397 × 10 ^-10 , A14 = -2.28012 × 10 ^-12 , A16 = -1.63935 × 10 ^-13 , A18 = 2.288889 × 10 ^-15

Aspherical surface, eighth surface

• K = 0.0, A4 = -6.58062 × 10 ^-5 , A6 = 1.14936 × 10 ^-6 , A8 = -1.26545 × 10 ^-7 , A10 = 3.77974 × 10 ^-9

Aspherical surface, fifteenth surface

• K = 0.0, A4 = 2.08131 × 10 ^-4 , A6 = 4.65854 × 10 ^-6 , A8 = 2.28057 × 10 ^-7 , A10 = -2.79019 × 10 ^-9

Aspherical surface, sixteenth surface

• K = 0.0, A4 = -4.28029 × 10 ^-6 , A6 = 2.20357 × 10 ^-6 , A8 = -7.52231 × 10 ^-8 , A10 = 1.35906 × 10 ^-9

Variable distance End of short focal length Between focal length End of the long focal length f = 5.97 or intermediate focal length f = 16.89 f = 10.05 A 19,290 4,720 1,510 B 3,130 7,820 19.070 C 5,144 5,618 3,110

Numerical values of the conditional expression or the conditional equation

• (R _c2 / R _c4 ) = 0.608

Embodiment 11:

• f = 5.93 x 16.86, F = 2.80 x 4.67, ω = 39.18 x 15.54

Aspherical surface; fourth surface

• K = 0.00, A4 = -2.32229 × 10 ^-4 , A6 = -6.31837 × 10 ^-6 , A8 = 4.27101 × 10 ^-7 , A10 = -2.21703 × 10 ^-13 , A12 = 4.78981 × 10 ^-10 , A14 = -6.35199 × 10 ^-15 , A16 = 1.36560 × 10 ^-13 , A18 = 1.51878 × 10 ^-15

Aspherical surface, eighth surface

• K = 0.0, A4 = -1.16901 × 10 ^-4 , A6 = -3.08214 × 10 ^-8 , A8 = -6.84811 × 10 ^-8 , A10 = 1.84472 × 10 ^-9

Aspherical surface, sixteenth surface

• K = 0.0, A4 = -4.24072 × 10 ^-5 , A6 = 5.73436 × 10 ^-6 , A8 = -2.30527 × 10 ^-7 , A10 = 3.88547 × 10 ^-9

Variable distance End of short focal length Between focal length End of the long focal length f = 5.93 or intermediate focal length f = 16.86 f = 10.04 A 20,290 8,280 1,520 B 4,070 9,240 18,250 C 4,205 4,046 3,131

Numerical values of the conditional expression or the conditional equation

• (R _c2 / R _c4 ) = 0.748

Embodiment 12:

• f = 5.89 x 16.89, F = 2.82 x 4.82, ω = 39.16 x 15.52

Aspherical surface; fourth surface

• K = 0.00, A4 = -3.15459 × 10 ^-4 , A6 = -8.13580 × 10 ^-6 , A8 = 4.08027 × 10 ^-7 , A10 = -2.24087 × 10 ^-8 , A12 = 4.71948 × 10 ^-10 , A14 = -8.86171 × 10 ^-13 , A16 = -1.42043 × 10 ^-13 , A18 = 1.59011 × 10 ^-15

Aspherical surface, eighth surface

• K = 0.0, A4 = -7.63659 × 10 ^-5 , A6 = 6.37036 × 10 ^-7 , A8 = -1.16821 × 10 ^-7 , A10 = 3.74070 × 10 ^-9

Aspherical surface, fifteenth surface

• K = 0.0, A4 = 1.00867 × 10 ^-4 , A6 = 2.91679 × 10 ^-7 , A8 = -3.63439 × 10 ^-7 , A10 = 9.13541 × 10 ^-9

Aspherical surface, sixteenth surface

• K = 0.0, A4 = -3.89759 × 10 ^-5 , A6 = 5.94128 × 10 ^-6 , A8 = -2.59750 × 10 ^-7 , A10 = 4.43344 × 10 ^-9

Variable distance End of short focal length Between focal length End of the long focal length f = 5.98 or intermediate focal length f = 16.89 f = 10.05 A 18,670 8,190 1,500 B 4,390 10,260 18.590 C 3,741 30.94 3,120

Numerical values of the conditional expression or the conditional equation

• (R _c2 / R _c4 ) = 0.771

Embodiment 13:

• f = 5.97 x 16.89, F = 2.62 x 4.50, ω = 39.22 x 15.50

Aspherical surface; fourth surface

• K = 0.00, A4 = -3.50415 × 10 ^-4 , A6 = -7.96879 × 10 ^-6 , A8 = 4.26960 × 10 ^-7 , A10 = -2.31083 × 10 ^-8 , A12 = 4.71718 × 10 ^-10 , A14 = -5388042 × 10 ^-13 , A16 = -1.64984 × 10 ^-13 , A18 = 1.38887 × 10 ^-15

Aspherical surface, eighth surface

• K = 0.0, A4 = -5.40074 × 10 ^-5 , A6 = 2.6888 × 10 ^-7 , A8 = -4.69765 × 10 ^-8 , A10 = 1.63234 × 10 ^-4

Aspherical surface, fifteenth surface

• K = 0.0, A4 = 4.355436 × 10 ^-6 , A6 = -2.32623 × 10 ^-6 , A8 = 1.07805 × 10 ^-7 , A10 = -1.44986 × 10 ^-6

Aspherical surface, sixteenth surface

• K = 0.0, A4 = -4.43447 × 10 ^-5 , A6 = 6.39748 × 10 ^-6 , A8 = -2.82100 × 10 ^-7 , A10 = 4.82472 × 10 ^-9

Variable distance End of short focal length Between focal length End of the long focal length f = 5.98 or intermediate focal length f = 16.89 f = 10.05 A 19,290 7,510 1,500 B 3,690 8,580 19,167 C 4,287 4,703 3,046

Numerical values of the conditional expression or the conditional equation

• (R _c2 / R _c4 ) = 0.623

Embodiment 14:

• f = 5.87 x 16.87, F = 2.60 x 4.3082, ω = 39.22 x 15.54

Aspherical surface; fourth surface

• K = 0.00, A4 = -4.18878 × 10 ^-4 , A6 = -5.57084 × 10 ^-6 , A8 = 2.33800 × 10 ^-8 , A10 = -4.13692 × 10 ^-9 , A12 = 8.10103 × 10 ^-11 , A14 = -3.20280 × 10 ^-12 , A16 = 8.61126 × 10 ^-14 , A18 = -1.22318 × 10 ^-15

Aspherical surface, eighth surface

• K = 0.0, A4 = -7.69893 × 10 ^-5 , A6 = 1.97480 × 10 ^-7 , A8 = -6.39629 × 10 ^-8 , A10 = 1.50880 × 10 ^-9

Aspherical surface, fifteenth surface

• K = 0.0, A4 = -7.59877 × 10 ^-5 , A6 = -1.20101 × 10 ^-5 , A8 = 6.80472 × 10 ^-7 , A10 = -5.79809 × 10 ^-5

Aspherical surface, sixteenth surface

• K = 0.0, A4 = -5.31574 × 10 ^-5 , A6 = 5.73963 × 10 ^-6 , A8 = -3.63619 × 10 ^-7 , A10 = 1.26225 × 10 ^-9 , A12 = 1.64982 × 10 ^-16

Variable distance End of short focal length Between focal length End of the long focal length f = 5.97 or intermediate focal length f = 16.87 f = 10.04 A 19,780 8,290 1,500 B 5,460 10.890 19.928 C 3,893 3,715 3,321

Numerical values of the conditional expression or the conditional equation

• (R _c2 / R _c4 ) = 0.755

Embodiment 15:

• f = 5.97 x 16.88, F = 2.81 x 4.66, ω = 39.21 x 15.54

Aspherical surface; fourth surface

• K = 0.00, A4 = -3.95739 × 10 ^-4 , A6 = -5.46578 × 10 ^-6 , A8 = 2.46770 × 10 ^-8 , A10 = -4.03062 × 10 ^-9 , A12 = 8.48853 × 10 ^-11 , A14 = -3.59858 × 10 ^-12 , A16 = 9.71936 × 10 ^-14 , A18 = -1.29965 × 10 ^-15

Aspherical surface, eighth surface

• K = 0.0, A4 = -7.11513 × 10 ^-5 , A6 = -2.25641 × 10 ^-7 , A8 = -2.93083 × 10 ^-8 , A10 = 5.82303 × 10 ^-10

Aspherical surface, fifteenth surface

• K = 0.0, A4 = -6.85138 × 10 ^-5 , A6 = -6.23316 × 10 ^-6 , A8 = 4.84453 × 10 ^-8 , A10 = -2.39206 × 10 ^-8

Aspherical surface, sixteenth surface

• K = 0.0, A4 = -4.26984 × 10 ^-5 , A6 = 6.666642 × 10 ^-6 , A8 = -4.21681 × 10 ^-7 , A10 = 1.42976 × 10 ^-8 , A12 = -1,82438 × 10 ^-10

Variable distance End of short focal length Between focal length End of the long focal length f = 5.97 or intermediate focal length f = 16.88 f = 10.04 A 19,620 8,000 1,500 B 5,130 10,260 19.820 C 3,985 4,068 3.162

Numerical values of the conditional expression or the conditional equation

• (R _c2 / R _c4 ) = .789

The 42 to 44 show the aberration curve of the zoom object according to the embodiment 9. The 42 is the aberration curve at the end of the short focal length of the zoom lens according to the embodiment 9, wherein 43 the aberration curve at the intermediate focal length is, or is 44 the aberration curve at the end of the long focal length.

The 44 to 47 show the aberration curve of the zoom lens of the embodiment 10. 45 is the aberration curve at the end of the short focal length of the zoom lens according to the embodiment 10, wherein 46 the aberration curve at an intermediate focal length is, or 47 is the aberration curve at the end of the long focal length. The 48 to 50 show the aberration curve of the zoom lens according to the embodiment 11. The 48 is the aberration curve at the end of the short focal length of the zoom lens according to the embodiment 11, wherein 49 the aberration curve at the intermediate focal length is or 50 is the aberration curve at the end of the long focal length.

The 51 to 53 show the aberration curve of the zoom lens according to the embodiment 12. The 51 is the aberration curve at the end of the short focal length of the zoom lens according to the embodiment 12, wherein 52 the aberration curve at the intermediate focal length is, or is 53 the aberration curve at the end of the long focal length.

The 54 to 56 show the aberration curve of the zoom lens according to the embodiment 13. The 54 is the aberration curve at the end of the short focal length of the zoom lens according to the embodiment 13, wherein the 55 the aberration curve at the intermediate focal length is, or is the 56 the aberration curve at the end of the long focal length.

The 55 to 59 show the aberration curve of the zoom lens according to the embodiment 14. The 57 is the aberration curve at the end of the short focal length of the zoom lens according to the embodiment 14, wherein the 58 is the aberration curve at the intermediate focal length. or is that 59 the aberration curve at the end of the long focal length.

The 60 to 62 show the aberration curve of the zoom lens according to the embodiment 15. The 60 is the aberration curve at the end of the short focal length of the zoom lens according to the embodiment 14, wherein the 61 the aberration curve at the intermediate focal length is, or is the 62 the aberration curve at the end of the long focal length.

In each view of the aberration, a broken line indicates a sine condition with respect to the spherical aberration. A solid line indicates sagittal or arrowwise, respectively, and indicates the dashed line meridionally with respect to the aspheric aberration.

Since the digital camera equipped with the zoom lens of the second kind has completely the same structure as the camera of the first kind, its description is omitted.

The invention relates to a zoom lens which comprises a first group of lenses ( 1 ), which has a negative focal length, a second group of lenses ( 2 ), which has a positive focal length, and a third group of lenses ( 3 ) having a positive focal length, in order from an object side in which the second group of lenses (FIG. 2 ) is monotonically movable from an image side to the object side, and the first group of lenses ( 1 ) is movable to correct a positional shift of an image plane, which is accomplished by a change in magnification when the magnification is changed from an end of the short focal length to the end of the long focal length. The zoom lens is characterized in that the first group of lenses ( 1 ) has at least two lenses (L1) and (L2) and an air lens formed between the two lenses, both sides of the air lens and the virtual lens being an aspheric surface, and the first group of lenses satisfies the following conditional expressions: no> 1.50 and ni> 1.60, where no indicates a refractive index to the d-line of the lens disposed on the object side in the air lens and the virtual lens, respectively Refractive index to the d-line of the lens or the lens disposed on the image page in the air lens or the virtual lens displays.

Claims (20)

Zoom lens, which is a first group of lenses ( 1 ), which has a negative focal length, a second group of lenses ( 2 ), which has a positive focal length, and a third group of lenses ( 3 ), which has a positive focal length, in the order from an object side, and in which the second group of lenses ( 2 ) monotone from an image page ( 15 ) is movable to the object side and the first group of lenses ( 1 ) is movable to correct a positional shift of an image surface, which is accomplished with a magnification change, when the magnification is changed from one end of the short end of the focal length to the end of the long focal length, the zoom lens comprising the second group of lenses ( 2 ) a positive lens, a negative lens whose convex surface opposes the object side, a positive meniscus lens whose convex surface is opposite to the object side and includes a positive lens in order from the object side. Zoom lens according to claim 1, characterized in that it satisfies the following expressions: 1.0 <(Rn + Rp) / 2Ymax <1.5 and -0.5 <(Rn × Rp) / (Rn + Rp) <0, wherein Rn indicates a radius of curvature of an image side surface of the negative meniscus lens in the second group of lenses, Rp indicates the radius of curvature of the object side surface of the positive meniscus lens in the second group of lenses, and Ymax indicates a maximum image height. Zoom lens according to claim 1, characterized in that at least the negative meniscus lens and the positive meniscus lens are fixedly arranged in the second group of lenses. Zoom lens according to claim 3, characterized in that it satisfies the following expressions: 0.8 <Rc / Ymax <1.2 where Rc indicates the radius of curvature of the fixed surface and Ymax indicates the maximum image height. Zoom lens according to any one of claims 1 to 4, characterized in that it comprises an iris integral with the second group of lenses ( 2 ) on the object side of the second group of lenses ( 2 ) is movable, and that has at least one surface that the object side of the second group of lenses ( 2 ) and is formed to be an aspherical surface. A camera having an optical system with a zoom lens according to any one of claims 1 to 5. Zoom lens that contains a first group of lenses ( 1 ), which has a negative focal length, a second group of lenses ( 2 ), which has a positive focal length, a third group of lenses ( 3 ), which has the positive focal length, in the order of an object side, and an iris, which together with the second group of lenses ( 2 ) is movable toward the object side of the second lens group in which the second group of lenses is monotonically movable from an image side to the object side, and wherein the first group of lenses is movable to correct a positional shift of an image surface, with a change magnification is accomplished when the magnification is changed from a short focal length end to the long focal length end, the zoom lens having the second group of lenses (Figs. 2 ) has a three-element lens array including a negative lens, a positive lens, and the negative lens in the order from the object side fixed to each other, characterized in that a refractive index Nc2 and a Abbe number νc2 of the positive lens is arranged at the center of the three-element lens array in the second group of lenses satisfying the following conditions: 1.45 <Nc2 <1.52 and 68 <νc2 <85. A zoom lens according to claim 7, characterized in that the negative lens, which is located in the three-element lens array of the second group of lenses of the object side closest, has a meniscus shape whose concave surface is opposite to the image side. A zoom lens according to any one of claims 7 or 8, characterized in that the strongly concave surface in the negative lens is opposite to the image side closest to the image side in the three-element lens array of the second group of lenses. The zoom lens according to claim 7, characterized in that a refractive index Nc1 and a negative lens Abbe number vc1 closest to the object side of the three-element lens array in the second group of lenses and a refractive index Nc3 and a negative lens Abbe number vc3 which is located on the image side of the lens array in the second group of lenses which satisfy the following conditions: 1.60 <Nc1 <1.95, 20 <νc1 <40, 50 1.60 <Nc3 <1.95, and 20 <νc3 <40. A zoom lens according to claim 10, characterized in that the refractive index Nc1 and the negative lens Abbe number νc1 farthest on the object side of the three-element lens array in the second array of lenses satisfy the following conditions: (3.1) 1, 75 <Nc1 <1.95 and (4.1) 20 <νc1 <35. A zoom lens according to claim 10, characterized in that the refractive index Nc1 and the negative lens Abbe number vc1 farthest on the object side of the three-element lens array in the second group of lenses satisfy the following conditions: (3.1) 1, 75 <Nc1 <1.95 and (4.1) 35 <νc1 <40. A zoom lens according to claim 10, characterized in that the refractive index Nc1 and the negative lens Abbe number νc1 farthest on the object side of the three-element lens array in the second group of lenses satisfy the following conditions: (3.1) 1.60 <Nc1 ≤ 1.75 and (4.1) 20 <νc1 <35. A zoom lens according to any one of claims 7, 8 or 9, characterized in that a radius of curvature of the fixed surface on the object side Rc2 and a radius of curvature of the image side nearest surface Rc4 of the three-element lens array in the second group of lenses satisfy the following conditions: ( 7) 0.5 <(Rc2 / Rc4) <0.85. A zoom lens according to any one of claims 7 to 13, characterized in that the radius of curvature of the fixed surface on the object side Rc2 and the radius of curvature of the image side nearest surface Rc4 of the three-element lens array in the second group of lenses satisfies the following condition: (7) , 5 <(Rc2 / Rc4) <0.85. Zoom lens according to one of claims 7 to 14, characterized in that the second group has at least one positive lens on either the object side or on the image side of the three-element lens arrangement. A zoom lens according to claim 16, characterized in that at least one of the positive lenses disposed on the object side and the image side of the three-element lens array has the aspherical surface. A zoom lens according to claim 16 or 17, characterized in that the first group has two negative lenses and one positive lens in the order from the object side. A zoom lens according to claim 17, characterized in that the first group has two negative lenses and a positive lens in order from the object side. Camera, characterized in that it comprises the zoom lens according to one of claims 7 to 19 as an optical pickup system.

Images